Experimental evaluation

Catalyst performance & electrode testing

Electrochemical screening, short-term stability measurements and hydrogen-production tests support our catalyst development.

Metal screening · Linear sweep voltammetry

Metal cubes · 1 cm² · 6 M KOH · 200 mV/s · RHE

LSV curves compare the electrochemical response of the tested metals. At a comparable hydrogen-evolution current, a potential closer to 0 V vs. RHE indicates a lower required overpotential. Anodic current may include surface oxidation, charging or dissolution as well as oxygen evolution; it should not be interpreted as oxygen production alone.

Metal foils · Linear sweep voltammetry

1 cm² · 6 M NaOH · 200 mV/s · RHE

LSV comparison of metal foils in 6 M NaOH

The tested foils show different cathodic and anodic responses. Pt reaches the illustrated hydrogen-evolution currents at potentials closer to 0 V vs. RHE than Au. A lower potential at the same oxygen-evolution current can indicate a lower overpotential, provided the current is attributable to oxygen production. Rankings apply only to the tested electrodes and conditions.

Short-term current stability

Chronoamperometry · 6 M KOH · up to 100 s

Current–time responses at several applied potentials provide an initial view of operational stability. Relatively constant current indicates a steadier response over this short measurement window; it does not by itself establish corrosion resistance or long-term durability.

Time-dependent electrode response

Chronoamperometry · 6 M KOH · up to 100 s

The changing current illustrates a time-dependent electrode response. Surface modification, activation, passivation and gas-bubble dynamics may contribute. Additional measurements are needed to distinguish these effects from material degradation.

Ru/Ni electrodes · Hydrogen production

6 M KOH · 70 °C · plotted from the supplied measurement table

Ru-coated electrodes deliver a higher measured hydrogen flow at the shared voltage points in this dataset. At 2.00 V, the reported flow is 672 mL/min, compared with 540 mL/min for cleaned Ni and 528 mL/min for original nanoNi/Ni. These comparisons apply to the specific test conditions shown.

Electrode comparison · Measurement data

6 M KOH · 70 °C

U (V)*	Aqua-regia-cleaned Ni			Ru-coated Ni			Original nanoNi/Ni
U (V)*	I (A)	P (W)	H₂ (mL/min)	I (A)	P (W)	H₂ (mL/min)	U (V)	I (A)	P (W)	H₂ (mL/min)
1.70	13.9	23.7	80	24.6	44.6	160	1.80	35.7	66.8	264
1.80	28.0	52.1	210	44.3	86.1	320	1.90	52.7	105.3	432
1.90	43.1	85.8	340	68.3	141.7	484	2.00	66.7	142.0	528
2.00	60.4	127.2	540	95.2	209.2	672	2.10	83.5	189.3	640
2.05	66.1	144.6	548	109.3	248.2	840	2.18	100.1	238.5	784

*The first voltage column applies to both cleaned Ni and Ru-coated Ni. Values are transcribed from the supplied table; current, power and flow are retained as reported.

51 kWh/kg H₂Reported Ru/Ni energy consumption

≈77%Energy efficiency · HHV basis

55 kWh/kg H₂Reported pure-Ni comparison · ≈72% HHV

Reported specific energy consumption is approximately 7% lower for Ru/Ni than for pure Ni. The HHV-based efficiencies use 39.4 kWh/kg divided by the reported electricity consumption. Faradaic efficiency and percentage production gains require their measurement basis and reference conditions to be specified before publication.